Express this product in scientific notation: $(7.90\times 10^{-3})\times (5.00\times 10^{5})$
Start by collecting like terms together. $= (7.90\times 5.00) \times (10^{-3}\times 10^{5})$ When multiplying exponents with the same base, add the powers together. $= 39.5 \times 10^{-3\,+\,5}$ $= 39.5 \times 10^{2}$ To write the answer correctly in scientific notation, the first number needs to be between $1$ and $10$ . In this case, we need to move the decimal one position to the left without changing the value of our answer. $ $ We can use the fact that $39.5$ is the same as $3.950 \times 10$ $ = {3.950 \times 10} \times 10^{2} $ $= 3.950\times 10^{3}$